Read it through once

That is true. The surest way for a nation’s scientific men to prove that they were proud and ignorant was to claim to have found out something fresh in the course of a thousand years or so. Evidently the people of this book’s day regarded themselves as children, and their remote ancestors as the only grown-up people that had existed. Consider the contrast: without offence, without over-egotism, our own scientific men may and do regard themselves as grown people and their grandfathers as children. The change here presented is probably the most sweeping that has ever come over mankind in the history of the race. It is the utter reversal, in a couple of generations, of an attitude which had been maintained without challenge or interruption from the earliest antiquity. It amounts to creating man over again on a new plan; he was a canal boat before, he is an ocean greyhound to-day. The change from reptile to bird was not more tremendous, and it took longer.